In this work, we have studied the excluded-volume effects on dilute solution properties of atactic polystirene with fixed stereochemical composition (the fraction of racemic diads f_r=0.59), atactic poly(methyl methacrylate) with f_r=0.79, and pol13EA\ : yisobutylene with fixed structure of chain ends over a wide range of molecular weight M from oligomers and polymers. The obtained findings are summarized as follows :1)A quasi-two-parameter scheme is valid for the gyration-radius expansion factor alpha_s. That is, alpha_s may be expressed as a function only of the scaled excluded-volume parameter * defined in the Yamakawa-Stockmayr-Shimada theory that takes a13EA\ : ccount of the effects of excluded-volume and chain stiffness on the basis of the helical wormlike (HW) chain. The conventional two-parameter theory does not hold for alpha_s because of chain stiffness. The effect of chain stiffness remains large ev13EA\ : en for M > 10^6.2)The quasi-two-parameter scheme is also valid for th
… Moree viscosity-radius expansion factor alpha_<eta> as in the case of alpha_s. The effect of chain stiffness on alpha_<eta> also remains large even for M > 10^6. The draining effect does not appear in13EA\ : alpha_<eta>, if it is not observed in the intrinsic viscosity [eta]_<(〕SY.horizontally divided circle.〔)> at THETA.3)The interpenetration function psi appearing in the second virial coefficient A_2 is not a function only of alpha_s, indicating that neither the conventional- nor the quasi-two-parameter scheme is valid for psi. psi depends separately on M and on13EA\ : the excluded-volume strength because of chain stiffness. The experimental results for psi are semi-quantitatively explained by the Yamakawa theory that takes account of the effect of chain stiffness on A_2.4)For small M, the effect of chain ends on A_2 is significant in both THETA and good solvents. The effect cannot be neglected even for relatively large M up to ca. 10^5. The observed M dependence of A_2 is quantitatively expressed by the Yamakawa13EA\ : theory that takes account of that effect on A_2. Less